NEW YORK (Reuters Health) - Using proteomic profiling, researchers have identified and validated several peptide biomarkers for occult intra-amniotic infection (IAI), a major and potentially preventable cause of preterm birth. This, they say, could lead to the development of rapid, noninvasive assays to detect subclinical IAI during pregnancy.
Such an assay would be “an important breakthrough,” Dr. Michael G. Gravett and colleagues write in the July 28th issue of the Journal of the American Medical Association, because “early diagnosis of IAI has been hindered by insensitive or nonspecific tests.”
Dr. Gravett of Oregon Health and Science University in Portland and associates characterized amniotic fluid peptides in 19 pregnant rhesus monkeys before and after experimentally induced IAI. They identified a “unique amniotic fluid peptide profile” that appeared within 12 hours after IAI and was “reliably present before the onset of labor or other clinical signs or symptoms of infection.”
They subsequently validated this peptide profile in a cohort of women with subclinical IAI-associated preterm delivery and a control group of women without evidence of infection.
This peptide signature was present in all 11 women with subclinical IAI, in 2 of 11 with preterm delivery without IAI, and in none of 11 with preterm labor and term delivery without infection (P<0.001).
Peptide fragment analysis implicated calgranulin B and a unique fragment of insulin-like growth factor binding protein 1. Additional studies “confirmed the presence and differential expression” of these biomarkers in amniotic fluid and in maternal blood during, but not in the absence of, IAI.
Dr. Gravett and colleagues also report the identification of several infection-related immunoregulatory proteins “not previously described in amniotic fluid,” including the antibacterial proteins Fall-39 (LL-37) and azurocidin (CAP37).
“These diagnostic protein expression signatures, complemented by immunodetection of specific biomarkers in amniotic fluid and in maternal serum,” the investigators conclude, “might have application in the early detection of IAI.”
Source: JAMA 2004;292:462-469. [ Google search on this article ]
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